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woodguy7777
Sep 11, 2009, 06:42 PM
I have been running a few test using my computer cooling fan.
Just to experience using a multimeter for resistance testing. What I have found when I connect
My multimeter leads to the fan motor I get one resistance reading but if I swap the multimeter leads I get a diff reading. Is this normal?
Or is there a problem with my meter.
Thanks paul

Scleros
Sep 11, 2009, 08:23 PM
Computer fans are typically motivated by a brushless dc motor (http://en.wikipedia.org/wiki/Brushless_DC_electric_motor) which have an electronic controller to switch the current flow through the windings and are therefore not a purely resistive load. So yes, you probably will get different readings. Check your meter by measuring a purely resistive load, like a piece of wire, and swapping the leads.

Note very few devices in today's world are purely resistive.